I can't speak from experience, I'm a few months new to restoring compact Macs... but cleaning the drive would absolutely be my first thought if I were in your place. There's instructions here on how to re-lubricate a floppy drive... I don't know if additional cleaning instructions are necessary/exist, but this forum is crawling with that sort of information
I've considered cleaning the floppy drives in my Plus and SE/30, but they're working pretty fine as is so I haven't bothered yet.
Sorry if I'm no help, hehe, but as I said... cleaning the drive would be my first guess, and failing that, finding a replacement drive.